Sep 27, 2023 - Climate

Climate change made Austin's summer heat more likely

Where climate change most affected summer temperatures, 2023
Data: Climate Central; Note: A CSI of 3 or higher means human-caused climate change made the average daily temperature at least three times more likely; Map: Kavya Beheraj/Axios

Texas' record-breaking heat this summer would have been "virtually impossible" without human-caused climate change, per recent climate analyses.

Why it matters: Prolonged exposure to heat can make us ill, physically and mentally. And it can quickly turn deadly for vulnerable residents.

By the numbers: 63% of summer days in Austin this year had heat made three times more likely by climate change, per a new Climate Central report.

  • That's 57 out of 91 days.

How it works: Climate Central's analysis is based on the group's Climate Shift Index (CSI), which compares observed or forecast temperatures with simulations of the same weather conditions minus excess atmospheric greenhouse gases, Axios' Alex Fitzpatrick reports.

  • A CSI of 3, for example, means human-caused climate change made a given daily average temperature three times more likely.
  • While the analysis wasn't peer-reviewed, the methodology was.

Zoom in: EMS officials reported 778 cases of heat-related illnesses in Austin from June 1-Aug. 31, up from 648 in 2022 and 305 in 2021, according to data the department provided to Axios.

Of note: This year marked Austin's second-warmest summer on record — after 2011 — with an average summer temperature of 89.4.

  • National Oceanic and Atmospheric Administration measurements started in 1898 for the Austin area.

State of play: The city has taken steps to reduce the effects of climate change and adapt to extreme heat.

  • That includes installing heat-reflective coatings on pavement, deploying misting canopies in parks and turning libraries and other public buildings into cooling centers.

The big picture: In 45 of the 244 U.S. cities the group analyzed, at least half of all summer days had temperatures made at least twice as likely by climate change.

  • Victoria, southeast of Austin, had 80 days with heat made twice as likely by climate change.

What's next: Highs in the 90s are forecast to continue this week, and October temperatures are leaning above normal.


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